RU2396715C2 - Transmission device, data transmission method, reception device and data reception method - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention discloses a transmission device which includes a multiplexing unit which can multiplex a common pilot channel, a common control channel and a common data channel; a character generating unit made with possibility of inverse Fourier transformation of the multiplexed signal in order to generate a character; and a transmission unit which can transmit the generated character. The multiplexing unit is made with possibility of multiplexing the common control channel which contains control information necessary for demodulating the common data channel carrying useful information, and the common pilot channel which is designed for use by multiple users in the frequency domain, as well as multiplexing the common data channel in the time domain relative the said common pilot channel and the common control channel.

EFFECT: provision for support and increase in channel transmission efficiency even if the number of characters included in the transmission time interval can be reduced.

19 cl, 33 dwg

Description

FIELD OF THE INVENTION

The present invention generally relates to the field of mobile communication technology, and specifically relates to a transmitting device, a method for transmitting data, a receiving device and a method for receiving data for use in a mobile radio communication system using Orthogonal Frequency Division Multiplexing, OFDM).

State of the art

Mobile radio communication systems of the future, mainly focused on the reception and transmission of images and data, will require capabilities that far exceed the capabilities of traditional mobile communication systems (for example, a system based on IMT-2000 technology). For this purpose, it is necessary to increase the throughput, the exchange rate, increase the bandwidth, etc.

In the broadband mobile communication system, the problem of frequency selective fading caused by multipath propagation conditions arises, which makes OFDM technology a promising technology for next generation communication systems. In OFDM technology, guard intervals are added to active symbols, including the information to be transmitted, so as to form symbols, which in turn are transmitted one after the other at certain transmission intervals (TTI). Moreover, many TTI intervals form one frame. In addition, the formation of the guard interval is performed using part of the information contained in the active symbol. In some cases, the guard interval may be called a cyclic prefix (Cyclic Prefix, CP).

1 shows the relationship between a frame, a TTI interval, and a symbol. Since the receiver receives signals with various delays in the transmission channel, intersymbol interference occurs. However, with OFDM technology, such intersymbol interference can be significantly reduced, as long as the propagation delays during transmission fit into the duration of the guard interval.

During one TTI interval, various channels are transmitted. These channels may include a common pilot channel, a common control channel, and a common data channel. A common pilot channel is used by multiple subscribers to demodulate a common control channel. More precisely, the common pilot channel is used for channel estimation, synchronous detection, received signal quality measurement, etc. A common control channel is used to demodulate a common data channel that includes useful information (traffic information channel). Information on standard signal formats, including the pilot channel, is contained, for example, in Non-Patent Document 1.

Non-Patent Document 1. Keiji Tachikawa. "W-CDMA mobile communications method", MARUZEN Co., Ltd., pp. 100-101.

When transmitting information, the TTI interval is used to define various information blocks. For example, the TTI interval defines a block of a transmitted data packet, an update block for a method of modulating data and channel coding in a Modulation and Coding Scheme (MCS), an error correction coding block, a retransmission block for an automatic repeat request (Automatic Repeat reQuest , ARQ), a packet scheduling block, and the like. Under such circumstances, the duration of the TTI interval and thus the frame duration should be kept constant. However, the number of characters included in the TTI may vary randomly depending on the application or system.

In various conventional transmission methods, a common pilot channel is assigned to one or more symbols in the TTI, and a control channel or data channel is assigned to other symbols in the same TTI. Assuming that one symbol is occupied by a common pilot channel, while a TTI consists of ten symbols, then the common pilot channel occupies 10% of the TTI interval (1/10). On the other hand, if we assume that one symbol is occupied by a common pilot channel, while a TTI consists of five symbols, then the common pilot channel already occupies 20% of the TTI interval (1/5). Therefore, a decrease in the number of symbols included in the TTI leads to a problem of reducing the transmission efficiency of the data channel. In particular, this problem becomes significant when the number of characters in the TTI is reduced.

Disclosure of invention

Thus, the present invention is intended to solve the above problem and is directed to a transmitting device, a data transmission method, a receiving device and a data receiving method in which data transmission efficiency can be maintained or increased even when the number of characters included in the TTI is reduced.

An embodiment of the present invention provides a transmitting device comprising a multiplexing unit configured to multiplex a common pilot channel, a common control channel, and a common data channel; a symbol generating unit configured to inverse Fourier transform the multiplexed signal to form a symbol; and a transmitting unit configured to transmit the generated symbol. In this embodiment, the multiplexing unit multiplexes in the frequency domain of the common control channel, which includes the control information necessary for demodulating the common data channel, which carries useful information, and the common pilot channel, intended for use by multiple subscribers, and also performs time multiplexing areas of a common data channel with respect to said common pilot channel and common control channel. Even with a reduction in the number of symbols constituting a transmission time interval (TTI), the transmission efficiency of the channels, with the exception of the common pilot channel, can be maintained by correspondingly reducing the implementation intervals of the common pilot channel.

Thus, in accordance with the present invention, the transmission efficiency of the data channel can be maintained or increased even if the number of characters included in the TTI is reduced.

Brief Description of the Drawings

Figure 1 depicts the relationship between the frame, the transmission time interval (TTI) and the symbol.

FIG. 2 is a block diagram of a transmitter according to an embodiment of the present invention.

FIG. 3 is a block diagram of a receiver according to an embodiment of the present invention.

4 shows an example channel configuration according to an embodiment of the present invention.

5 shows various channel configurations.

6 depicts various channel configurations including dedicated pilot channels.

7 depicts the relationship between the insertion interval, the duration of the symbol and the maximum delay time.

Fig. 8 is a diagram of a transmitter according to an embodiment of the present invention.

Figure 9 shows an example channel configuration in accordance with the present invention.

10 is a diagram of a transmitter according to an embodiment of the present invention.

11 depicts a sector beam and a directional beam.

12 illustrates an example channel configuration in accordance with an embodiment of the present invention.

13 shows a MIMO multiplexing method according to an embodiment of the present invention.

On Fig shows an example configuration of a channel corresponding to a variant implementation of the present invention.

15 shows various channel configurations for common pilot channels.

16 shows a channel configuration for dedicated / common pilot channels.

On Fig schematically shows the pilot channels for transmission by multi-beam.

On Fig schematically shows the pilot channels for transmission by adaptive directional beam.

On Fig shows an example of the assignment of dedicated / common pilot channels in accordance with TDM technology.

On figa shows the dependence of bandwidth on the average value of the value of E _s / N ₀ when changing the number N _{stg of the} slot in which the step display was performed.

FIG. 20B shows an example of channel mapping for the N _{stg numbers of} slots 0, 1, and 2 where stepwise mapping was performed.

On figa schematically shows a mobile radio using pilot sequences orthogonal to each other between sectors.

21B illustrates a pilot channel generating unit for use in a transmitter according to an embodiment of the present invention.

On Fig shows a particular example of orthogonal pilot sequences.

On Fig shows a particular example of orthogonal pilot sequences.

24 shows the relationship between the scrambling code and the orthogonal code.

25 is a first example in which a common pilot channel and other channels are multiplied by a scrambling code and an orthogonal code.

FIG. 26 shows a second example in which the common pilot channel and other channels are multiplied by a scrambling code and an orthogonal code.

On Fig depicts a combination of examples shown in Fig and 26.

On Fig shows the pilot channel and the data channel of the useful signal and the unwanted signal.

On Fig shows intersector orthogonal sequences for the pilot MIMO channels.

30 is a diagram for explaining CAZAC sequences.

On Fig shows the pilot channel and the data channel of the desired signal and unwanted signal.

LIST OF REFERENCE NUMBERS

From 202-1 to 202-K: data channel generation unit.

210: spectrum spreading and channel coding unit.

212: interleaving unit.

214: data modulation unit.

216: block display in the time / frequency domain.

204: common pilot channel multiplexing unit.

206: block (IFFT) fast inverse Fourier transform.

208: guard interval generation unit.

302: guard interval removal unit.

304: fast Fourier transform block.

308: channel estimation unit.

310: dedicated pilot channel allocation unit.

312: block extracting data from the time / frequency domain.

314: data demodulation unit.

316: de-interleaving unit.

318: block narrowing the spectrum and channel decoding.

72: dedicated pilot channel control unit.

74: a dedicated pilot channel multiplexing unit.

102: a dedicated pilot channel multiplexing unit.

104: antenna weight control unit

106: weighting unit

2102: pilot sequence generation unit.

2104: a scrambling code generating unit.

2106: orthogonal code generating unit.

2108, 2110: multiplication block.

2502, 2504: forming unit.

2506: scrambling code generating unit.

2508: orthogonal code generating unit.

2510, 2512, 2514: multiplication block.

2602: scrambling code generation unit.

2604: multiplication block.

The implementation of the invention

In accordance with one aspect of the present invention, a common pilot channel and a common data channel are temporarily multiplexed, and a common control channel and a data channel are temporarily multiplexed. Since the common pilot channel is allocated not the entire frequency band, but only a part or part of the subcarriers, other channels except the common pilot channel are allocated other subcarriers in the symbol. By changing the location of the introduction of the common pilot channel in the frequency domain, you can also change the proportion of the common pilot channel in the symbol. Therefore, even when there is a reduction in the number of symbols making up the TTI (and the time interval per symbol becomes longer), it is possible to maintain the transmission efficiency of channels other than the common pilot channel by correspondingly reducing the number of insertion frequencies of the common pilot channels.

In accordance with another aspect of the present invention, time-domain multiplexing is provided for a dedicated pilot channel for use by one or more specific subscribers to demodulate a common data channel, as well as a combination of a common pilot channel and a common control channel. By estimating the channels using a dedicated pilot channel, in addition to the common pilot channel, the accuracy of channel estimation and similar parameters is improved.

The dedicated pilot channel undergoes time multiplexing at the first instant in constant frequency intervals, and also undergoes time multiplexing at the second instant in the indicated constant frequency intervals. By dispersing the pilot channels in the time and frequency domain, the diversity effect of the pilot channel can be improved and the transmission efficiency of other channels, with the exception of the pilot, can be increased.

The dedicated pilot channel is transmitted to the radio participant, which moves at an increased speed, but it is not necessary to transmit it to the radio participant, whose movement speed is low. By transmitting a dedicated pilot channel only to a subscriber whose channel fluctuation in the time domain is considered large, it is possible to exclude the transmission of a dedicated channel when it is not required.

In the transmitting device, an antenna (beam) beam pattern regulator can be provided that adjusts the directivity of the transmitted beam to a particular communication participant. The inclusion of a dedicated pilot channel can be made for a particular participant in the communication. When a directional beam is used, the channel performance is different from beam to beam. Through the use of a dedicated pilot channel directed to a particular communication participant, in addition to the common pilot channel, the accuracy of channel estimation is improved.

When the MIMO multiplexing method is used, the pilot channel can be transmitted from one or more transmitting antennas, and the dedicated pilot channel can be transmitted from another one or more transmitting antennas, which allows adequate transmission of the MIMO multiplexing method depending on the class of the receiving device (more precisely, the number receiving antennas).

In accordance with another aspect of the present invention, there is provided a receiving device comprising a receiving unit adapted to receive a symbol transmitted by a transmitter, a conversion unit for performing a Fourier transform of a received symbol, and a separation unit for extracting a common pilot channel, a common control channel and a common channel from the converted signal data. The separation unit allocates in the frequency domain a common pilot channel used by a plurality of subscribers to demodulate a common control channel, and a common control channel used to demodulate a common data channel, and in the time domain, the separation unit allocates a common data channel including useful information and a combination of a common pilot channel and common control channel.

In accordance with another aspect of the present invention, in a transmitter, a common pilot channel is multiplied by an spreading code sequence (scrambling code) common to multiple sectors, and an orthogonal code sequence that varies from sector to sector, and the resulting signal is transmitted to a communication party (usually a mobile station ) Since one sector differs from other sectors not by a scrambling code, but by an orthogonal code, one can easily and with high accuracy distinguish sectors, thereby improving the quality of the pilot channel.

The remaining channels, in addition to the common pilot channel, can be multiplied by the spreading code sequence (scrambling code), common to many sectors, and the orthogonal code sequence, which differs from sector to sector.

From the spreading code sequence common to many sectors, a different spreading code is derived in accordance with a predetermined rule, and other channels can be multiplied by this output spreading code except for the pilot channel. Moreover, although different scrambling codes are used for the pilot channel and other channels, these scrambling codes can be easily found by applying the indicated code generation rule.

The pilot channel and the common control channel can be multiplied by the spreading code sequence (scrambling code) common to many sectors and the orthogonal code sequence, which differs from sector to sector, and the common data channel can be multiplied by another extension code. In this case, the scrambling codes can be used accordingly, for example, based on the requirements of changing the spectrum expansion coefficient.

Regarding the following examples of embodiments, although the present invention is described in the context of a system that uses OFDM technology in the downlink, other systems that employ, for example, multi-subcarrier technology can be used.

First Embodiment

2 shows a portion of a transmitter according to a first embodiment of the present invention. Although this transmitter is usually provided in the base station of the mobile communication system, as described in the present embodiment, the specified transmitter can be provided in other devices. The transmitter contains several blocks 202-1 through 202-K of forming a data channel, the number of which is K, a common pilot channel multiplexing unit 204, an Inverse Fast Fourier Transformation (IFFT) block 202, and a guard interval generating unit 208. Since K blocks of data channel formation 202-1 through 202-K have identical functions and construction, the first data channel formation block 202-1 in the following description represents the remaining blocks. The data channel generating unit 202-1 comprises a spreading and channel coding unit 210, an interleaver 212, a data modulation unit 214, and a time and frequency domain display unit 216.

Block 202-1 formation of the data channel produces the formation of the data channel for the first subscriber. Although, to simplify the presentation, processing for one subscriber is performed by one data channel generating unit, for a single subscriber, multiple data channel generating units can be used.

The spectrum spreading and channel coding unit 210 performs channel coding in the data channel to be transmitted, thereby increasing the device's ability to correct errors. It should be noted that the spreading of the spectrum by spreading code sequences in this particular embodiment of the invention is not performed, since OFDM technology is used here. However, when other embodiments employ Orthogonal Frequency and Code Division Multiplexing (OFCDM) technology, the spreading and channel coding unit 210 performs both channel coding and spreading with spreading codes in the data channel to be transmitted . As channel coding, turbo coding can be used.

The interleaver 212 changes the symbol order of the channel-encoded signal in the time domain and / or in the frequency domain in accordance with a predetermined rule known to the transmitter and receiver with which the radio is communicating.

The modulation unit 214 translates the signal to be transmitted into the space (constellation) of signal states in accordance with a suitable modulation method. As the modulation method, various methods can be used, such as QPSK, 16QAM, 64QAM, or the like. When an Adaptive Modulation and Coding Scheme (AMCS) is used, the modulation method and channel coding rate are assigned on an individual basis.

The time and frequency domain mapper 216 determines how the data channels to be transmitted are mapped to the time and / or frequency domain.

The common pilot channel multiplexing unit 204 multiplexes the common pilot channels, common control channels, and data channels, and also outputs the multiplexed channels. Multiplexing can be carried out in the time domain, in the frequency domain, or jointly in both the time and frequency domains.

IFFT unit 206 performs fast inverse Fourier transform of the signal to be transmitted, or modulation in accordance with OFDM technology, which forms the active part of the symbol.

The guard interval generating unit 208 extracts a fragment of the active part of the symbol and adds the extracted fragment to the end of the active part of the symbol, thereby forming a transmitted symbol (transmitted signal).

Blocks 202-1 through 202-K of forming a data channel produce the formation of data channels to be transmitted to respective subscribers. In blocks 202-1 through 202-K of forming a data channel, data channels are channel encoded, interleaved, modulated, and mapped to a time / frequency domain. After the display, the data channels appear at the outputs of the respective data channel generation blocks 202-1 through 202-K and are input to the multiplexing unit 204 of the common pilot channel, in which the data channels are multiplexed together with the common pilot channels and common control channels. The multiplexed signal undergoes a fast inverse Fourier transform, and a guard interval is added to the signal that underwent the transformation (active part of the symbol), and thereby the transmitted symbol is formed. The transmission of the transmitted symbol is made through a radio frequency unit (not shown).

Figure 3 shows a portion of the receiver corresponding to the considered embodiment of the present invention. Despite the fact that, as shown in this example, this receiver is usually provided in a mobile station of a mobile communication system (for example, in the equipment of subscriber # 1), the receiver can be provided in other devices. The receiver includes a guard interval removal unit 302, a Fast Fourier Transformation (FFT) unit 304, a common pilot channel allocation unit 306, a channel estimator 308, a dedicated pilot channel allocation unit 310, and time and frequency domain data extraction unit 312, a data demodulation unit 314, a de-interleaving unit 316, and a spectrum narrowing and channel decoding unit 318.

The guard interval removal unit 302 removes the guard interval from the transmitted symbol and, thus, extracts the active part of the symbol.

Block 304 FFT performs fast Fourier transform of the signal or demodulation in accordance with OFDM technology.

A common pilot channel allocator 306 allocates each subcarrier demodulated in accordance with OFDM technology so as to obtain common pilot channels, common control channels, and other channels.

The channel estimator 308 performs channel estimation using the allocated common pilot channels and provides a control signal for channel compensation to the data demodulator 314 or a similar block. Such a control signal is also used to compensate for the channel for common control channels, although this is not shown in the diagram for simplicity.

A dedicated pilot channel allocation unit 310 is not used in the present embodiment, but is used to extract dedicated pilot channels from other channels in the embodiment described below. The dedicated pilot channels are provided to a channel estimator 308 and are used to increase the accuracy of the channel estimator.

Block 312 extracting data from the time and frequency domain extracts the data channels in accordance with the display rule, which sets the transmitter, and provides the extracted data channels.

A data demodulation unit 314 performs channel compensation, and then demodulates the data channels. The demodulation method corresponds to the modulation method, which was carried out in the transmitter.

The deinterleaving unit 316 changes the order of the symbols of the data channel according to the interleaving operation that was carried out at the transmitter.

Block 318 narrowing the spectrum and channel decoding performs channel decoding of the received data channels. Since OFDM technology is used, the narrowing operation is not performed in the present embodiment. However, in other embodiments, when OFCDM technology is used, the spectral narrowing and channel decoding unit 318 performs both spectral narrowing and channel decoding of the received data channels.

The signal received by the antenna (not shown) passes through a radio frequency unit (not shown), is converted into a signal of the main frequency band, is subjected to the removal of the guard interval and fast inverse Fourier transform. From the converted signal, common pilot channels are extracted that are used for channel estimation. In addition, common control channels and data channels are extracted from the converted signal and then demodulated. The demodulated data channels undergo de-interleaving and channel decoding operations, and thus, data transmitted by the transmitter is restored.

Figure 4 shows how, in this embodiment, the multiplexing of various channels is performed. As an example, 20 transmission TTI intervals are included in a 10 ms frame, which means that one TTI is 0.5 ms. One TTI is composed of 7 characters located in the time domain (N _D = 7).

In the example shown in the drawing, common pilot channels, common control channels, dedicated pilot channels, and data channels are multiplexed. Dedicated pilot channels are described in the second embodiment of the invention and further. Common pilot channels and common control channels undergo frequency multiplexing within a single symbol. More precisely, the implementation of common pilot channels in certain frequency intervals in the first TTI symbol is performed. On the other hand, common data channels are transmitted by the second character and subsequent characters in the same TTI. Namely, the common pilot channels and the common data channels undergo time multiplexing, and the common control channels and the data channels also undergo time multiplexing. Since not all the frequency band in the TTI is allocated to the common pilot channels, but only part of the frequency band or part of the subcarriers, other subcarriers can be allocated to the remaining channels, except for the common pilot channels. By varying the implementation intervals of the common pilot channels in the frequency domain, the proportion of the common pilot channels in the TTI can be adjusted. For example, when the number of symbols in the TTI is reduced (and the time interval per symbol is correspondingly extended), it is possible to maintain the transmission efficiency of channels other than the common pilot channel by correspondingly reducing the number of implementation frequencies of the common pilot channels.

5 shows various examples of channel configurations in which common pilot channels and common control channels are multiplexed. It should be noted that channel configurations are not limited to the illustrated examples; on the contrary, other channel configurations can be implemented. The channel configuration 1 shown in FIG. 5 is the same as the channel configuration shown in FIG. 4. As already mentioned, common pilot channels are used for channel estimation to demodulate common control channels. With channel 1 configuration, since the common pilot channels and common control channels are frequency multiplexed, there are no common pilot channels for a subcarrier that contains common control channels, and therefore, with channel 1 configuration, the channel estimate value for the common control channels cannot be obtained directly. Therefore, the channel estimate value for the common control channel has to be obtained by interpolating the channel estimate values for subcarriers that contain common pilot channels. As interpolation, linear interpolation can be used. By the way, the bidirectional arrows in FIG. 5 indicate that interpolation is performed on the marked area. In this particular example, since all common pilot channels and common control channels are assigned to the first symbol, demodulation of the common data channels can be carried out quickly. In addition, since the common pilot channels and the common control channels are distributed widely in the frequency domain, the effect of the frequency separation can be enhanced and the resistance to frequency selective fading can be increased.

With a configuration of 2 channels, common pilot channels and common control channels undergo time multiplexing. With this configuration, no interpolation is required, unlike the configuration of 1 channels. In addition, common pilot channels and common control channels are distributed widely in the frequency domain, which increases the resistance to frequency selective fading.

When configuring 3 channels, common control channels are implemented after part of the common pilot channels and are not implemented after the remaining common pilot channels. These common pilot channels and common time-domain multiplexed control channels allow for power control during transmission. With this configuration, since the common control channels are implemented such that the TTI interval essentially overlaps in the time domain, it is necessary to carry out channel estimation throughout the entire TTI interval. In this case, if only common pilot channels in the first symbol are used for channel estimation, the accuracy of the channel estimate for the last symbol is not sufficiently guaranteed. In particular, the situation worsens when the receiver moves at an increased speed, because in this case the fluctuations in time become very significant. Therefore, the channel estimate value obtained from the first symbol in the TTI interval and the channel estimate value obtained from the last symbol in the TTI interval are used so as to optimally estimate the channel (for example, by linear interpolation).

When configuring 4 channels, the common control channels are multiplexed by frequency hopping in the time and frequency domain. Since common pilot channels and common control channels are distributed widely in the frequency domain, the resistance to frequency selective fading can be increased. In addition, since the common pilot channels and the common control channels are also distributed in the time domain, it is possible to perform power control during transmission.

Second Embodiment

In a second embodiment of the present invention, dedicated pilot channels are used in addition to common pilot channels. These channels are identical to common pilot channels in that they are used for channel estimation and similar operations. However, they differ in that the dedicated pilot channels are used only for a specific mobile station, while the common pilot channels are used for all mobile stations. Therefore, while only one type of signal can be prepared as a signal indicating a common channel, many signals must be prepared as signals indicating dedicated pilot channels, and their number is greater than the number of mobile phones. Dedicated pilot channels are used when mobile phones move at an increased speed, when a downlink beam is used in the downlink, and when the mobile stations have a predetermined number of receiving antennas, or in similar cases, as described in more detail below.

6 shows various channel configurations including dedicated pilot channels. The channel configurations are not limited to the illustrated examples; on the contrary, other channel configurations can be implemented. With the configuration of 1 channels of FIG. 6, dedicated pilot channels are embedded at predetermined intervals in the second symbol. With the configuration of 2 channels of FIG. 6, dedicated pilot channels are implemented as a frequency hopping in both the time and frequency domain. When configuring the 3 channels of FIG. 6, dedicated pilot channels undergo time multiplexing after part of the common pilot channels, but not after the remaining common pilot channels. With a configuration of 4 channels of FIG. 6, dedicated pilot channels and common data channels are code-multiplexed.

As for the common pilot channels and dedicated pilot channels, when estimating the channel in the time domain, the intervals Δ _{P of the} implementation of the pilot channels must satisfy the sampling theorem. More precisely, the intervals Δ _P implementation are set in such a way as to satisfy the following dependencies:

Δ _P < T _s / d _max

where T _s represents the duration of the active part of the symbol (the duration of the symbol obtained after removing the guard interval), ad _max represents the maximum value of the propagation delay on the path. This dependence is presented in Fig.7. For example, when T _s and d _max are 80 μs and 20 μs, respectively, insertion intervals should be 4 or less.

Third Embodiment

FIG. 8 shows a portion of a transmitter according to a third embodiment of the present invention. In Fig. 8, elements that have already been discussed in connection with Fig. 2 are given similar indices. As shown, the data channel generating unit 202-1 further comprises a dedicated pilot channel control unit 72 and a dedicated pilot channel multiplexing unit 74. These elements are also provided in other blocks 202-2 through 202-K of forming a data channel. The dedicated pilot channel control unit 72 determines, in accordance with the mobility of the mobile station in question, whether to introduce the dedicated pilot channels into the signal to be transmitted to the mobile station. Mobility can be measured, for example, based on the maximum Doppler frequency shift. If the mobility according to the measurement data exceeds a predetermined level, then dedicated pilot channels can be introduced. The dedicated pilot channel multiplexing unit 74 introduces or does not introduce the dedicated pilot channels into the signal to be transmitted, in accordance with the instruction received from the dedicated pilot channel control unit 72, and outputs to the common pilot channel multiplexing unit 204 a signal containing or not containing dedicated pilot canals.

For example, the mobile station shown in FIG. 3 notifies the base station of any signs that the base station can use to determine if the mobile station has moved at an increased speed. Such a sign may be the maximum Doppler frequency shift, but not only it alone. When the dedicated pilot channel control unit 72 determines that the mobile station is moving at an increased speed, the dedicated pilot channels are multiplexed together with the signal in the dedicated pilot channel multiplexer 74. Otherwise, multiplexing of the dedicated pilot channels is not performed. In this example, the dedicated pilot channels are introduced into the transmitted signal for a fast moving mobile station, while the dedicated pilot channels are not introduced into the signal to be transmitted to a slowly moving or stationary station. Dedicated pilot channels are used in addition to common pilot channels for fast moving mobile stations, thereby increasing the accuracy of channel estimation.

Figure 9 shows an example channel configuration when the frequency band is divided into many frequency blocks. One frequency block includes several subcarriers. Such a frequency block may also be called a resource block. A subscriber can use one or more frequency blocks in accordance with the transmitted information (data volume, etc.). In the above example, frequency block 1 is used by a fast moving subscriber, while the common data channels and dedicated pilot channels are multiplexed in frequency block 1. Additionally, another frequency block 2 is used by a subscriber who does not move fast, and in frequency block 2, dedicated pilot channels are not multiplexed . In the case of a fast moving mobile station, since the channel estimate value can vary significantly from one moment in time to another, both common pilot channels and dedicated pilot channels are used, due to which the channel estimate value is obtained with high accuracy. On the other hand, in the case of a stationary or slowly moving mobile station, it is expected that the channel estimate value will not vary significantly from one point in time to another. If both common pilot channels and dedicated pilot channels are transmitted to such a subscriber, this can lead to a decrease in data transmission efficiency, since the transmission of optional pilot channels is performed. However, the dedicated pilot channel estimator 72 determines the mobility of the mobile station and determines whether to transmit dedicated pilot channels in accordance with the measured mobility, thereby preventing useless transmission of the dedicated pilot channels.

Fourth Embodiment

10 shows a portion of a transmitter according to a fourth embodiment of the present invention. In Fig. 10, elements that have already been discussed in connection with Fig. 2 are given similar indices. In this embodiment, multiple antennas are used to transmit the signal. In this regard, the data channel generation unit 202-1 is additionally equipped with a dedicated pilot channel multiplexing unit 102, an antenna weight control unit 104 and a weight coefficient setting unit. Moreover, each of the multiple antennas is equipped with elements such as a common pilot channel multiplexing unit 204, IFFT unit 206, and a guard interval forming unit 208 or similar units. The dedicated pilot channel multiplexing unit 102 multiplexes the dedicated pilot channels to form a signal to be transmitted. The antenna weight control unit 104 controls the weight of each of the plurality of antennas. Corresponding regulation of the weight coefficients allows one to obtain a radiation pattern that has a directivity in a certain direction or does not have any directivity. The weighting factor setting unit 106 sets a weighting factor for each transmitting antenna in accordance with a control signal from the antenna weighting control unit 104. Usually the weighting factor is expressed by the amount of phase shift to which the amplitude can be added.

By the way, common pilot channels and common control channels must be transmitted to all subscribers, while dedicated pilot channels must be transmitted to a specific subscriber. Therefore, the common pilot channels and the common control channels are transmitted by a sector beam, which captures the entire sector, and the dedicated pilot channels are transmitted by a directional beam having a directivity towards the subscriber. 11 schematically shows a sector beam and directional rays. 11, a sector beam capturing the entire sector and having a radiation pattern with an angle of 120 ° is shown by a solid line, while directional rays having a narrower radiation pattern and aimed at subscriber 1 and subscriber 2, respectively, are shown by dashed lines.

12 is an example channel configuration when a frequency band is divided into a plurality of frequency blocks. One subscriber, in accordance with the transmitted information (data volume, etc.), can use one or more frequency blocks. In this example, frequency block 1 is used by subscriber 1, and frequency block 2 is used by subscriber 2. Since, in addition to common pilot channels transmitted throughout the sector, each subscriber can use dedicated pilot channels transmitted by directional beam, it is possible to estimate the channel with high accuracy in accordance with the direction of the directed beam.

Fifth Embodiment

In a fourth embodiment of the invention, multiple transmit antennas are used to form one directional beam. On the other hand, in a technology with multiple receiving and transmitting antennas (Multi-Input Multi-Output, MIMO), multiple antennas are used independently so as to transmit different signals from respective antennas at the same frequency together, while receiving said signals is multiple receiving antennas, and the separation of these signals is performed using the appropriate signal separation algorithm. The independent use of multiple transmitting antennas can create multiple propagation paths of the transmitted signal (transmission channels) and thereby increase the data rate by a factor corresponding to the number of transmitting antennas. Since the transmission channels are formed by the respective antennas, the pilot channels are transmitted by the respective antennas, and channel estimation is also performed for the respective antennas. In addition, when the number N _TX transmit antennas and the number N _RX receive antennas are different, the transmission must be performed in accordance with the smallest number of antennas. For example, when the base station transmits signals from four antennas, then the transmission speed that can be expected for transmission from four antennas cannot be obtained if the mobile station has only two receiving antennas - a throughput that can be realized only by two of the four transmitting antennas antennas. In other words, if a mobile station has only two antennas, then the use of four antennas of a base station cannot contribute to an increase in data transmission efficiency. Based on this, in the fifth embodiment of the present invention, the transmission method from the radio base station is changed in accordance with the number of receiving antennas provided at the mobile station.

To simplify the description, it is assumed that the mobile station has two or four antennas, and four antennas are installed at the base station, although the embodiment being considered is applicable to a situation where the mobile station and the base radio station have any suitable number of antennas. In this embodiment, the reception of common pilot channels and common control channels is performed by a mobile station of any type, and the allocation of dedicated pilot channels is performed by a mobile station with four antennas.

13 schematically shows a MIMO technology in accordance with an embodiment of the present invention. As shown, the transmission of the common pilot channels (and common control channels) is carried out from the first antenna and from the second transmitter antenna (base radio station). Common pilot channels are used by all mobile stations. In addition, dedicated pilot channels are transmitted from the third antenna and the fourth antenna. Dedicated pilot channels are used only by a receiver (mobile station) having four antennas.

On Fig presents an example configuration of the channel when the frequency band is divided into many frequency blocks. One subscriber can use one frequency block or several frequency blocks in accordance with the content of the transmitted information (data size, etc.). In the example shown, frequency block 1 is used by subscriber 2, and frequency block 2 is used by subscriber 1. Common pilot channels and common control channels in the first TTI slot are transmitted from the first and second transmit antennas. The second symbol and the subsequent ones in the frequency block 2 are used to transmit common data channels to the subscriber 1, which has only two antennas. The second symbol and the subsequent ones in frequency block 1 are used to transmit dedicated pilot channels from the third and fourth antennas to subscriber 2, which has four antennas. This results in an increase in throughput for subscriber 1 and subscriber 2.

On Fig shows several methods of multiplexing related to the common pilot channels. However, for the present embodiment, in addition to the methods shown, various other multiplexing methods are applicable. In method 1, multiplexing of the common pilot channels is performed only in the frequency domain, which corresponds to the multiplexing method shown in Fig. 14. In method 2, multiplexing of common pilot channels is performed in the time and frequency domains. With method 3, multiplexing of the common pilot channels is performed only in the time domain.

Sixth Embodiment

Downlink pilot channels may be divided into common pilot channels and dedicated pilot channels. Common pilot channels can be transmitted by sector beam or multi-beam due to the use of several antennas with fixed weighting factors (fixed radiation pattern). When multi-beam is used, the capture of the entire sector is made by a certain number of directed rays.

Common pilot channels can be used to indicate the sector to which the subscriber in question belongs, from among many sectors of the same cell. All sectors of one cell use scrambling codes specific to that cell. Common pilot channels can be used to search within a cell and handover, or to measure a reference level in adjacent cells / sectors. In addition, common pilot channels can be used for quality measurement in order to obtain channel quality information (CQI) for scheduling packet transmission in accordance with the instantaneous channel quality value. The CQI parameter can be used with adaptive control of the communication channel. Common pilot channels can be used to estimate the physical channel transmitted by a sector beam or multi-beam.

Dedicated pilot channels can be transmitted by a sector beam, a multi-beam, or an adaptive beam (adaptive directional beam) obtained in an adaptive manner for each subscriber. The adaptive directional beam and the directional beam, which is part of the multi-beam, are one and the same in the sense that the beam-forming antenna has a large gain in a certain direction. However, the directional beam is formed at constant weights, while the weights of the adaptive directional beam vary in accordance with the position of the mobile station. More specifically, the directional beam is a fixed directional beam, while the adaptive directional beam is a directional beam with a variable directivity, i.e. directionality that can be changed. Dedicated pilot channels may be transmitted by means of an adaptive beam generated in an adaptive manner for each subscriber. Dedicated pilot channels can be used as auxiliary for estimating a physical channel transmitted by a sector beam or multi-beam, although common pilot channels are mainly used for channel estimation. Dedicated pilot channels can be used to estimate the physical channel transmitted by the adaptive beam. Dedicated pilot channels can be used to measure the CQI of the physical channel transmitted by the adaptive beam.

On Fig shows an example channel configuration of the common pilot channels and dedicated pilot channels. In the presented example, common pilot channels are mapped onto subcarriers in predetermined frequency intervals within one symbol (or one time slot). On the other hand, dedicated pilot channels are mapped onto subcarriers at predetermined frequency intervals within another symbol or several symbols (or one time slot). By the way, common pilot channels can be displayed in one character or several characters.

Common pilot channels can be transmitted by a sector beam and used to demodulate the physical channel, namely, for channel estimation and reception synchronization. In addition, common pilot channels can be transmitted from a transmitter that uses MIMO technology. Moreover, dedicated pilot channels can additionally be used in accordance with the characteristics of the subscriber or radio conditions in order to improve the accuracy of channel estimation. When a specific frequency block used for common data channels is used by only one or several subscribers, certain dedicated pilot channels can be additionally used in accordance with the transmission conditions for a particular subscriber (speed of movement, delay spread, signal-to-noise ratio for the received signal ( Signal-to-interference plus Noise power Ratio (SINR), etc.), and thereby the accuracy of channel estimation can be further improved. In the multicast / broadcast channel, dedicated pilot channels are additionally used to account for subscribers with the worst transmission conditions in the cell in question, thereby improving the accuracy of channel estimation. On the other hand, the operations of measuring the reference level to search for a cell or handover, as well as measuring CQI for scheduling packet transmission, adaptive control of a communication channel, or similar tasks are basically performed using common pilot channels, but can be additionally performed using dedicated pilot channels.

Common pilot channels can be used to demodulate a physical channel transmitted by a multi-beam, more specifically, for channel estimation and reception synchronization. In addition, as in the case of the sector beam, the dedicated pilot channels can be additionally used in accordance with the characteristics of the subscriber or radio conditions, and thereby the accuracy of channel estimation can be improved. On the other hand, the operations of measuring the reference level to search for a cell or handover, as well as measuring CQI for scheduling packet transmission, adaptive control of a communication channel, or similar tasks are basically performed using common pilot channels, but can be additionally performed using dedicated pilot channels. When many beams operate in the same cell, the pilot sequences used to determine which beam a particular subscriber belongs to can be reused in the same cell, thereby reducing the number of pilot sequences.

On Fig schematically shows the pilot channels transmitted by the multi-beam. In the presented example, five directional beams (fixed radiation patterns) are used. The pilot sequence is reused by two directional beams, the direction of which, among the five indicated beams, is significantly different from each other.

Since the adaptive radiation pattern creates rays that are transmitted adaptively directed to the respective subscribers during transmission, dedicated pilot channels are used to estimate the channel. In addition, in order to improve the accuracy of channel estimation, in addition to the dedicated pilot channels, common pilot channels can also be used, when the channels have an increased correlation between multi-beam transmission and adaptive-beam transmission. On the other hand, the measurement of the reference level to search for a cell or handover, as well as the CQI measurement for scheduling packet transmission, adaptive control of the communication channel and similar tasks, is carried out in principle using common pilot channels transmitted by a sector beam or multi-beam.

On Fig shows the pilot channels transmitted by the adaptive directional beam.

The common pilot channels and dedicated pilot channels may be periodically multiplexed in each TTI. Depending on the subscriber and radio conditions, dedicated channels are used to increase the accuracy of channel estimation. When a single frequency block is used exclusively by one subscriber or several subscribers in relation to common data channels, for example, in situations of high mobility, large delay spread or extremely low SINR, in addition to common pilot channels, dedicated pilot channels are assigned, thereby improving the accuracy of channel estimation . In the multicast / broadcast channel, dedicated pilot channels are used in addition to the common pilot channels, thereby improving communication quality for a subscriber who has had the worst communication quality before. Additional subscriber-specific information on the dedicated pilot channel in the common data channels is provided by the control signaling channel. Therefore, using a larger number of pilot symbols under conditions of small delays, it is possible to realize high-quality demodulation of common data channels. In the multicast channel / broadcast channel, additional information depending on the communication conditions of the dedicated pilot channel is provided by the signaling channel based on the quality of the subscriber’s communication under the worst communication conditions. Using a larger number of pilot symbols in low latency conditions, a high-quality multicast / broadcast channel can be obtained.

The mapping of pilot channels can be performed with a higher density in the frequency domain than in the time domain. More channels can be assigned to the frequency domain than to the time domain. More specifically, the density of the pilot channels may be higher in the frequency domain than in the time domain. Although channel fluctuations in the time domain may be less significant when the TTI duration is relatively short, it is expected that channel fluctuations in the frequency domain become significant due to the temporal spread of frequency selective fading during multipath propagation of radio waves. Therefore, it is more advantageous to display pilot channels with a higher density than to distribute pilot channels, assigning them to subcarriers in accordance with the TDM method.

Multiplexing based on TDM and / or FDM technology can be applied by performing stepwise mapping from the start of the TTI. In stepwise display, as shown in FIG. 16, the channels are mapped at certain intervals in one time slot, while in other time slots, the channels are mapped at certain intervals at other frequencies. Common pilot channels and dedicated pilot channels may be mapped to each TTI in accordance with the step mapping principle. Mapping common pilot channels can be done with higher priority than dedicated channels. When pilot channels are mapped at the beginning of each TTI, at least the following advantages are apparent. When signaling channels are displayed at the beginning of each TTI along with common / dedicated pilot channels, these signaling channels are reliably demodulated by accurate channel estimation, even in situations where channel quality fluctuates due to differences in delay spread and Doppler frequency shifts. When signaling channels are displayed at the beginning of each TTI, and the frequency block does not transmit any useful information (traffic data), i.e. when only control signal bits are transmitted, it is desirable that the subscriber equipment effectively performs periodic (cyclic) reception.

Fig. 19 shows an example of fixing shared and dedicated pilot channels.

On figa shows the simulation results obtained in accordance with an embodiment of the present invention, in which a relationship is established between the ratio of the power per symbol to the spectral noise density (E _s / N ₀ ) and throughput. The three types of graphs in FIG. 20A correspond to the simulation results obtained, respectively, for the three numbers (N _stg = 0, 1, 2) of the time slots in which the pilot symbols were displayed in steps. The channel configurations corresponding to N _stg = 0, 1, 2, respectively, are presented in FIG. The curve with white circles in figa shows the dependence at N _stg = 0; the curve with shaded circles shows the dependence at N _stg = 1; and the curve with black circles shows the dependence at N _stg = 2. With this simulation, it was assumed that the speed of the mobile station is 120 km / h. As shown in FIG. 20A, as the number N _{stg of the} slot in which the pilot symbols are displayed stepwise increases, the throughput increases, which indicates the efficiency of the step display. This is believed to be due to improved monitoring capabilities in channel estimation in the time domain.

With the present method of displaying common pilot channels and dedicated pilot channels, the pilot symbols can be fixed in the frequency domain and in the time domain in an intermittent manner. For example, intermittent frequency domain OFDM symbol mapping may be applied. When the fixing of the pilot symbols in the frequency domain and in the time domain is carried out in an intermittent manner, with a spread, the following advantage is revealed. Firstly, since the thinning of the subcarriers assigned to the pilot symbols in the frequency domain occurs, it is possible to prevent a decrease in the data transmission efficiency caused by the introduction of the pilot symbols, while preserving the channel estimation accuracy comparable to the estimation accuracy that occurs when the thinning of the subcarriers is not going on. The amount of resource allocation in the time domain is reduced. With the actual implementation of cellular technology, the transmission power of the common pilot channels must be changed depending on the radius of the given cell. Therefore, the pilot symbols are punctured in the frequency domain, more precisely, the multiplexing and transmission of the pilot symbols and other channels is carried out in the same OFDM symbols, and thereby the total transmit power is supported and the transmit power of the common pilot channels is flexibly changed.

Seventh Embodiment

In a seventh embodiment of the present invention, a method is described in which orthogonal code sequences in sectors of the same cell are used. The considered method can be applied not only among the many sectors that are part of the cell, but also among the cells. With traditional W-CDMA technology, scrambling is performed using different spreading code sequences for different sectors; the received signal is scrambled with the appropriate scrambling codes so as to obtain pilot channels, and a channel estimation or similar operation is performed. Since scrambling codes that are different for each sector are randomly determined, the pilot channels are interfered with due to inter-code interference of symbols whose subcarrier and subframe are the same in the sector under consideration (intersector interference). As a result, it becomes relatively difficult to perform high-precision channel estimation and cell search, or even if channel estimation and cell search can be performed, it takes longer. This leads to inconvenience, especially when a mobile station requires fast handover, or if the station is moving, often crossing sector boundaries. With regard to this point, in conditions of multipath propagation of radio waves, the signal quality can be improved to some extent by using OFDM technology in the data channel of the downlink and eliminating the need to multiply the data channels by scrambling codes. However, since the pilot channels are multiplied by scrambling codes, which are different in order to distinguish sectors for different sectors, the reception quality of the pilot sectors is not significantly improved, which still makes it difficult to accurately estimate the channel and similar operations. The seventh embodiment of the invention was conceived in connection with this drawback and is aimed at improving the quality of reception of the pilot channels in the downlink in OFDM technology.

According to this embodiment, in addition to cell-specific orthogonal code sequences, sector specific orthogonal sequences are used in the pilot channels. In this case, the pilot channels are protected from interference from neighboring sectors of the same cell. Since this intersectoral interference is eliminated, the accuracy of channel estimation can be improved. Increasing the accuracy of channel estimation is beneficial when conducting parallel transmissions associated with the quick selection of sectors and their soft pairing.

On figa schematically shows the use of a pilot sequence orthogonal to sectors (or rays) corresponding to the considered embodiment. The subscriber station, which must undergo handover at the sector boundary, can perform parallel channel estimation based on pilot signals from two base stations, which makes it possible to estimate channels quickly and with high accuracy. For example, subscriber # 1, located on the boundary of the sector (more precisely, the subscriber who needs to perform quick sector selection or soft pairing of sectors), makes the distinction of sectors by narrowing the spectrum of orthogonal sequences to enable accurate channel estimation. The subscriber # 2, which does not need to make quick sector selection or soft pairing of sectors, can use each pilot symbol (or take into account the orthogonal code specific to the cell / sector) for channel estimation.

On figv presents the block forming the pilot channel used in the transmitter in accordance with this embodiment of the present invention. The base station is usually the transmitter. The pilot channel generating unit includes a pilot sequence unit 2102 that generates a channel pilot sequence, a scrambling unit 2104 that generates a scrambling code, and an orthogonal code unit 2106 that generates various spreading symbols (orthogonal codes) for different sectors, a multiplying unit 2108, which multiplies the scrambling codes by orthogonal codes, and a multiplying unit 2110 that multiplies the pilot sequence by an output from the multiplying unit 2108. The pilot sequence is known to the base station and the mobile station. The scrambling code is a random sequence intended for general use by multiple sectors. The determination of orthogonal codes is made for each sector so that the codes are orthogonal with respect to each other.

On Fig presents a particular example of multiplying orthogonal codes by a pilot sequence. As shown, the codes indicated in the form (1, 1, 1, 1, 1, 1, 1, 1, 1, ...) are mapped to the intervals of one subcarrier in sector # 1; the codes indicated in the form (1, -1, 1, -1, 1, -1, 1, -1, ...) are mapped to the intervals of one subcarrier in sector # 2, and the codes indicated in the form (1, -1 , -1, 1, 1, -1, -1, 1, ...) are mapped to the intervals of one subcarrier in sector # 3. These codes are orthogonal to each other.

On Fig presents another particular example of multiplying orthogonal codes by a pilot sequence. As shown, the codes indicated in the form (1, 1, 1, 1, 1, 1, 1, 1, 1, ...) are mapped to the intervals of one subcarrier in sector # 1; codes indicated in the form (1, e ^{j2 / 3π} , e ^{j2 / 3π} , 1, e ^{j2 / 3π} , e ^{j2 / 3π} , 1, e ^{j2 / 3π} , ...) are mapped to the intervals of one subcarrier in sector # 2; and the codes indicated in the form (1, e ^{j2 / 3π} , e ^{j2 / 3π} , 1, e ^{j2 / 3π} , e ^{j2 / 3π} , 1, e ^{j2 / 3π} , ...) are mapped to the intervals of one subcarrier in sector # 3 . Such codes may be orthogonal to each other.

24 shows the relationship between scrambling codes and orthogonal codes. In the presented example, it is assumed that there are 40 subcarriers in the existing frequency band, and various data types are associated with the respective subcarriers, so as to perform transmission in accordance with OFDM technology. It goes without saying that the numerical values presented are for example purposes only. The entire available system frequency band or one frequency block can act as a channel band. In this example, the scrambling code is expressed in 40 data sequences and mapped onto the corresponding subcarriers. In the drawing, numbers 1 through 40 related to the scrambling code express codes that form the scrambling code. The scrambling code shown in the drawing in the second line is shifted by one individual code from the scrambling code in the first line, since the specified scrambling code is transmitted so that the correspondence relation is shifted by one individual code along the frequency axis, although the two scrambling codes used are the same. In this case, the signal along the frequency axis can be averaged.

In the particular example shown in FIG. 22, the scrambling codes are multiplied by orthogonal codes (1, 1, 1, 1, ...), and the resulting codes are multiplied by the pilot sequence in sector # 1; scrambling codes are multiplied by orthogonal codes (1, -1, 1, -1, ...), and the resulting codes are multiplied by the pilot sequence in sector # 2; and scrambling codes are multiplied by orthogonal codes (1, -1, -1, 1, ...), and the resulting codes are multiplied by the pilot sequence in sector # 3. In the particular example shown in FIG. 23, the scrambling codes are multiplied by orthogonal codes (1, 1, 1, 1, ...), and the resulting codes are multiplied by the pilot sequence in sector # 1; scrambling codes are multiplied by orthogonal codes (1, e ^{j2 / 3π} , e ^{j2 / 3π} , ...), and the resulting codes are multiplied by the pilot sequence in sector # 2; and scrambling codes are multiplied by orthogonal codes (1, e ^{j2 / 3π} , e ^{j2 / 3π} , ...), and the resulting codes are multiplied by the pilot sequence in sector # 3.

25 shows an example in which common pilot channels and other channels are multiplied by a scrambling code and an orthogonal code. 25 shows a generating unit 2502 that generates a sequence for common pilot channels, an generating unit 2504 that generates a sequence for other channels, a scrambling code unit 2506 that generates a scrambling code, an orthogonal code unit 2508 that provides various sectors with different spreading codes sequences (orthogonal codes), a multiplication block 2510 that multiplies the scrambling code by an orthogonal code, another multiplication block 2512 that deduces the multiplication of the data sequence for other channels by the signal from the output of the multiplication block 2510, and another multiplication block 2514, which multiplies the pilot sequence by the signal from the output of the multiplication block 2512. As mentioned above, the scrambling code is determined uniformly for multiple cells, and orthogonal codes are determined so that they are different (orthogonal) for different cells. In the above example, the common pilot channels and other channels are multiplied by the same scrambling code and the same orthogonal code.

26 shows another example in which the common pilot channels and other channels are multiplied by a scrambling code and an orthogonal code. Here, the elements and components already described in connection with FIG. 25 are given the same numerals and are not described again. On Fig additionally shown block 2602 of the second scrambling code and block 2604 multiplication, which multiplies the second scrambling code by orthogonal code. The (first) scrambling code block 2506 generates a (first) scrambling code intended for general use by a plurality of sectors. In accordance with a predetermined rule that the block 2506 of the first scrambling code generates, the block 2602 of the second scrambling code generates a second scrambling code for the block 2604 multiplication. The output of multiplication block 2604 is multiplied by a data sequence for other channels (except common pilot channels). Therefore, other channels are multiplied by a second scrambling code and an orthogonal code, while common pilot channels are multiplied by a first scrambling code and an orthogonal code. In this case, the common pilot channels differ from other channels by their extension codes. In this example, since the second scrambling code can be obtained from the first scrambling code, the transmitter can easily search for any channel, since the rule for generating the code is known.

On Fig presents a combination of specific examples shown in Fig and 26. As an example of the implementation of the present invention can be used with any combination of channels, and not just the combination shown in Fig. The presented combination is advantageous in that the common data channels, the expansion coefficient of which can vary, can easily be distinguished from channels whose expansion coefficient is maintained at a constant level.

In addition to the aforementioned interference suppression in the pilot channels, transmission power can be adjusted in the common data channels.

On figa, b, C shows the signals received by a particular subscriber. Figa depicts a signal (desired or useful signal), which is to be received by a specific subscriber from a cell or sector with which the subscriber is connected. In the drawing, the pilot channel is shown to be higher than the data channel, since the transmission and reception of the pilot channel is carried out with greater electrical power than the data channel. Figv depicts a signal that is not a useful signal for the subscriber (unwanted signal). This unwanted signal means a signal from a cell (or sector) with which the subscriber has no connection, and for a useful signal, this signal is an interference signal. In this example, such interference to the pilot channel is suppressed because different orthogonal codes are used for the pilot channels of the desired signal and the pilot channels of the unwanted signal. FIG. 28C schematically shows that the transmitter power for transmitting a data channel from a radio base station (transmit power for an unwanted signal) is reduced, or the transmission is stopped, so that the interference between the useful signal and the unwanted signal is reduced by adjusting the transmission time or frequency bands in the downstream communication lines between radio base stations or sectors. More specifically, the transmit power for the unwanted signal is limited to a value less than the set value. In this case, interference between data channels, which are considered in the example of FIG. 28, can be suppressed. Or, the subscriber can perform soft pairing by parallel transmission of identical data channels instead of reducing the transmission power of the unwanted signal (if necessary, to zero).

Eighth Embodiment

In an eighth embodiment of the invention, mapping of orthogonal pilot channels for transmission by MIMO technology is described. Orthogonal multiplexed pilot channels can be used in technologies based on antenna gain control, such as MIMO multiplexing, MIMO diversity transmission, and adaptive antenna array transmission. For example, the transmission of pilot channels is carried out in accordance with the MIMO transmission technology from all transmitter antennas. This is because pilot channels require a measurement of the CQI for all signal transmission events. All auxiliary operation costs for common pilot symbols are the same regardless of the number of transmitting antennas, because for data channels the coverage of the corresponding areas within the cell is guaranteed by using MIMO technology during transmission. When transmitting using MIMO technology, an improvement in channel estimation is obtained through the additional use of dedicated pilot channels (in the case of transmission using MIMO technology from four antennas, the number of pilot symbols per antenna becomes equal to one quarter of the number of pilot symbols in the case of transmitting one antenna). For MIMO transmission, adaptive partial mapping of pilot symbols can be applied, more precisely, thinning of the pilot symbols from the sector beam transmission mode can be performed in accordance with the application scenario parameters, such as delay spread and travel speed.

On Fig shows the orthogonal sequence for the pilot MIMO channels between sectors for the case of the transmitter with four antennas. Dedicated pilot channels are used as an adjunct for channel estimation. In the drawing, indices # 1, # 2, # 3 and # 4 correspond to the first, second, third and fourth antennas.

Ninth Embodiment

In the examples of the seventh and eighth embodiments of the invention, the suppression of inter-cell and intersector interference of the pilot channels is performed by multiplying the pilot channels by orthogonal codes. Although the use of such orthogonal codes is preferred from the point of view of further suppressing interference, the use of these orthogonal codes is not necessary from the point of view of distinguishing between cells and / or sectors, on the contrary, non-orthogonal codes can be used. However, when a non-orthogonal code is used, expressed by a random sequence of a general form, an important issue may be the deterioration of the quality of the pilot channels caused by inter-code interference, considered at the beginning of the description of the seventh embodiment of the invention. On the other hand, there are some types of non-orthogonal codes that are less problematic in terms of inter-code interference (correlation) compared to non-orthogonal codes expressed by random sequence. Such a code with high correlation characteristics (for example, a code that allows inter-code interference, on average, within one tenth of the code length) can be used to distinguish between cells and / or sectors. An example of such code is the CAZAC sequence, which is briefly described below.

As shown in FIG. 30, it is assumed that the length of one CAZAC sequence A sequence is L. For simplicity of explanation, it is assumed that the length L of this sequence corresponds to the time interval L of the implementations, although this assumption is not necessary. A series of implementations Δ (shown in the figure by hatching), including the last implementation (implementation L) of CAZAC sequence A, is shifted to the beginning of CAZAC sequence A, and thus another CAZAC sequence is formed - sequence B, as shown in Fig. 30 below. In this case, the sequences A, B of the CAZAC are orthogonal to each other, under the assumption that Δ varies from Δ = 1 to L-1. More specifically, the first CAZAC sequence is orthogonal to the second CAZAC sequence formed by cyclically shifting the first CAZAC sequence. Therefore, when preparing one CAZAC sequence having a length L, it is theoretically possible to prepare a group of L sequences that are orthogonal to each other. In addition, one CAZAC sequence A is not orthogonal to another CAZAC sequence B that was not produced from the CAZAC sequence A. However, even in this case, the inter-code interference of the indicated CAZAC sequences A and B is not significant compared to the inter-code interference between different random sequences. Moreover, the inter-code interference between a code sequence composed of part of a CAZAC sequence A and a code sequence composed of another part of a CAZAC sequence A is less significant compared to inter-code interference between different random sequences. For more detailed information on CAZAC sequences, see "Polyphase codes with good periodic correlation properties", D. C. Chu, IEEE Trans. Inform. Theory, vol. IT-18, pp. 531-532, July 1972; and "On allocation of uplink sub-channels in EUTRA SC-FDMA", 3GPP, R1-050822, Texas Instruments.

Tenth Embodiment

In the seventh, eighth or ninth embodiments of the invention, the pilot channels of the wanted signal and the unwanted signal are transmitted in parallel. In the example of the tenth embodiment, the pilot channels of the wanted signal and the unwanted signal are transmitted from the radio base station either at different times, or at different frequencies, or using both methods at once, as shown in Fig. 31. In this case, suppression of inter-cell or intersector interference in relation to the pilot channels can be performed. In addition, interference between the useful and unwanted signals can be suppressed further if transmission of the useful signal data channels is prohibited while pilot channels of the unwanted signal are being transmitted.

Although the present invention has been described with examples of preferred embodiments, the invention is not limited to the examples given, and changes may be made to the form and details of the invention without departing from the spirit and scope of the invention. In addition, for convenience, the invention is described with reference to separately presented embodiments. However, for the present invention, the individual status of the options is not significant, and, if necessary, one or more preferred options can be used together.

This international patent application is based on priority applications of Japan 2005-174400, 2005-241905 and 2006-031752 filed with the Japanese Patent Office on June 14, 2005, August 23, 2005 and February 08, 2006, the entire contents of which are included in the present invention by reference.

Claims (19)

1. A transmitting device comprising:
a multiplexing unit configured to multiplex a common pilot channel, a common control channel, and a common data channel;
a symbol generating unit configured to inverse Fourier transform the multiplexed signal to generate a symbol; and
a transmitting unit configured to transmit the generated symbol;
the multiplexing unit is capable of multiplexing a common control channel including control information necessary for demodulating a common data channel that carries useful information and a common pilot channel intended for use by multiple subscribers in the frequency or time domain, or both these areas, as well as with the possibility of multiplexing a common data channel in the frequency or time domain, or in both of these areas, relative to the common lotnogo channel and common control channel. 2. The transmitting device according to claim 1, characterized in that the multiplexing unit is configured to multiplex a dedicated pilot channel intended for use by one or more specific subscribers to demodulate a common data channel, in the frequency or time domain, or in both of these areas, relative to the common pilot channel and the common control channel. 3. The transmitting device according to claim 2, characterized in that the dedicated pilot channel is subjected to temporary multiplexing at the first time in predetermined frequency intervals, and also is subjected to temporary multiplexing at the second instant in the specified predetermined frequency intervals. 4. The transmitting device according to claim 2, characterized in that the dedicated pilot channel is transmitted to a radio participant that moves at high speed, and not to another radio participant that does not move at high speed. 5. The transmitting device according to claim 2, characterized in that it further comprises a unit that controls the directivity of the transmitted beam to a specific radio participant, while a dedicated pilot channel is formed for the specified specific radio participant. 6. The transmitting device according to claim 2, characterized in that it further comprises a plurality of transmitting antennas, wherein a common pilot channel is transmitted from one or more antennas from said plurality of transmitting antennas, and a dedicated pilot channel is transmitted from any other one or more antennas from the specified set of transmitting antennas. 7. The transmitting device according to claim 2, characterized in that the display of the common pilot channel and the dedicated pilot channel in the frequency or time domain, or in both of these areas, is carried out in an intermittent manner. 8. The transmitting device according to claim 1, characterized in that the transmission of the common pilot channel is made by codes that are orthogonal between any cells or sectors. 9. The transmitting device according to claim 1, characterized in that the common pilot channel is formed from a single CAZAC sequence or part of a CAZAC sequence having a predetermined code length. 10. The transmitting device according to claim 8 or 9, characterized in that when transmitting a common data channel to a cell or sector for other cells and sectors, the transmission power of the common data channel is reduced below a specified level. 11. The transmitting device according to claim 8 or 9, characterized in that the transmission of the common pilot channel to the cell or sector is performed either at a different time, or at a different frequency, or at a different time and at a different frequency, unlike the common pilot channel, transmitted to another cell or sector. 12. The transmitting device according to claim 11, characterized in that when transmitting a common pilot channel to a cell or sector for other cells and sectors, the transmission power of the common data channel is reduced below a predetermined level. 13. A method of transmitting data containing operations in which:
multiplex a common pilot channel for use by multiple subscribers, and a common control channel that includes control information necessary for demodulating a common data channel that carries useful information in the frequency or time domain, or in both of these areas, and also multiplex the common a data channel in the frequency or time domain, or in both of these areas, relative to the common pilot channel and the common control channel;
perform the inverse Fourier transform of the multiplexed signal to form a symbol and
transmit the generated symbol. 14. A receiving device comprising:
a receiving unit configured to receive a symbol transmitted from the transmitter;
a transform unit configured to Fourier transform the received symbol; and
a separation unit configured to extract from the converted signal a common pilot channel, a common control channel, and a common data channel;
wherein the separation unit is configured to allocate a common pilot channel intended for use by a plurality of subscribers, and a common control channel including control information necessary for demodulating the common data channel in the frequency or time domain, or in both of these areas, and allocating a common data channel that carries useful information in the frequency or time domain, or in both of these areas, with respect to the common pilot channel and the common control channel. 15. A method of receiving data containing operations in which:
receive the character transmitted from the transmitter;
Fourier transforms the received signal and
allocating a common pilot channel intended for use by a plurality of subscribers, and a common control channel including control information necessary for demodulating a common data channel that carries useful information in the frequency or time domain, or in both of these areas, and also allocate a common a data channel in the frequency or time domain, or in both of these areas, relative to the common pilot channel and the common control channel. 16. A transmitting device comprising:
a generating unit configured to generate a common pilot channel for use by a plurality of mobile stations;
a multiplexing unit configured to multiplex two or more channels to be transmitted; and
a first multiplication unit configured to multiply the common pilot channel by an spreading code sequence common to multiple sectors, and an orthogonal code sequence different to different sectors. 17. The transmitting device according to clause 16, wherein the first multiplication unit is configured to multiply other channels except the pilot channel by an expanding code sequence common to many sectors and an orthogonal code sequence different for different sectors. 18. The transmitting device according to 17, characterized in that it further comprises:
an output unit, configured to output in accordance with a predetermined rule of another extension code sequence from the extension code sequence common to multiple sectors; and
a second multiplication unit configured to multiply other channels except the pilot channel by said output spreading code sequence. 19. The transmitting device according to p. 18, characterized in that the first multiplication unit is configured to multiply the common pilot channel and the common control channel by an expanding code sequence common to many sectors, and an orthogonal code sequence different for different sectors; and the second multiplication unit is configured to multiply the common data channel by the output expanding code sequence.

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